Internal-combustion engine



FIG. 1 is a front elevation view of an internal-combustion engine showing our new design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is left side elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a perspective view thereof.

The broken line showing portion of an internal-combustion engine is included for illustrating environmental structure and forms no part of the claimed design. 

The ornamental design for an internal-combustion engine, as shown and described. 